What Should I Do?

A couple of days 以前 I was on Ebay.com looking at MJ stuff and I saw this limited edition Billie Jean Doll, it was still in the box in mint condition. It looked AWESOME! I told my dad if he can get it for me for 圣诞节 and he didn't want to get it because it cost $70 and he thinks it's way too much for a doll. What can I say to convince him to buy it for me? Any ideas?